Tone generator for electronic exchange

Abstract

A tone supplying device generates various tone signals which an exchange can provide for public subscribers. Address signals generated by a counting operation of a first counter are inputted to a plurality of tone tables, which in turn successively output a tone signal corresponding to each of the address signals and provide same to a corresponding buffer through a corresponding latch. The first counter allows the tone selecting signals and the address signals to be generated in the tone tables so as to successively output corresponding tone signals therefrom and, at the same time, supply the tone selecting signals to the cadence selecting circuit so as to allow the cadence selecting circuit to select any one of cadence data inputted thereto from the cadence table and to output it. Thus, the cadence data selected by the cadence selecting circuit and outputted therefrom intermits tone signals successively outputted from the tone tables, the tone signals being inputted to a corresponding buffer so as to output it to PCM highway. A tone supplying device of the present invention can supply a desired tone using a simple counter without employing an expensive microprocessor in the design of the tone supplying device, thereby to reduce production cost in manufacturng the finished product.

What is claimed is:  
     
       1. A tone supplying device for an exchange, comprising: 
       a plurality of tone tables for storing a predetermined magnitude of successive tone signals not having a predetermined intermittence ratio in a table form therein, said tone tables comprising a number of tone tables depending on a type of tone signal;  
       a cadence table for generating cadence data intermitting the output of said plurality of tone tables, including said predetermined magnitude of successive tone signals, in a table form;  
       first counter means connected to inputs of said plurality of tone tables for performing a counting operation to obtain a counted output which is divided into more significant bits and less significant bits, said more significant bits being supplied as an address signal to said plurality of tone tables to enable them, and said less significant bits being supplied to said plurality of tone tables and said cadence table simultaneously, thereby outputting a counting signal so as to generate a tone selecting signal for intermitting corresponding successive tone signals and said predetermined magnitude of successive tone signals;  
       second counter means connected to an input of said cadence table for generating an address signal which is a reference of cadence in a regular period, and for supplying said address signal to said cadence table; and  
       a plurality of buffers for receiving and storing the successive tone signals generated by the plurality of tone tables, and for allowing a cadence signal outputted from the cadence table to intermit the stored successive tone signals to output them.  
     
     
       2. The device according to  claim 1 , further comprising: 
       inverter means disposed on a line applying a cadence signal to be inputted to said plurality of buffers for inverting the inputted cadence signal so as to provide an inverted cadence signal to said plurality of buffers; and  
       idle pattern supplying buffer means disposed on a line for applying a cadence signal from the cadence table for supplying an idle pattern, the idle pattern supplying buffer means being enabled if “on(continuous)” data are applied thereto, and wherein noise components are not generated if the tone signals outputted through said plurality of buffers comprise an “off(intermittent)” signal.  
     
     
       3. The device according to  claim 2 , further comprising cadence selecting circuit means disposed between said cadence table and said idle pattern supplying buffer means for applying said “on(continuous)” data to said idle pattern supplying buffer means. 
     
     
       4. The device according to  claim 1 , further comprising cadence selecting circuit means connected to said cadence table and responsive to a tone-select signal from said first counter means for performing a cadence selection operation. 
     
     
       5. The device according to  claim 1 , further comprising latch means connected between said plurality of tone tables and said plurality of buffers for performing a latch operation with respect to data provided by said plurality of tone tables to said plurality of buffers. 
     
     
       6. A tone supplying device for an exchange, comprising: 
       a plurality of tone tables for storing a predetermined magnitude of successive tone signals not having a predetermined intermittence ratio in a table form therein, said tone tables comprising a number of tone tables depending on a type of tone signal;  
       a cadence table for generating cadence data intermitting the output of said plurality of tone tables, including said predetermined magnitude of successive tone signals, in a table form;  
       first counter means connected to inputs of said plurality of tone tables for performing a counting operation to obtain a counted output which is divided into more significant bits and less significant bits, said more significant bits being supplied as an address signal to said plurality of tone tables to enable them, and said less significant bits being supplied to said plurality of tone tables and said cadence table simultaneously, thereby outputting a counting signal so as to generate a tone selecting signal for intermitting corresponding successive tone signals and said predetermined magnitude of successive tone signals; and  
       second counter means connected to an input of said cadence table for generating an address signal which is a reference of cadence in a regular period, and for supplying said address signal to said cadence table.  
     
     
       7. The device according to  claim 6 , further comprising buffer means for receiving and storing the successive tone signals generated by the plurality of tone tables, and for allowing a cadence signal outputted from the cadence table to intermit the stored successive tone signals to output them. 
     
     
       8. The device according to  claim 7 , further comprising inverter means disposed on a line applying a cadence signal to be inputted to said plurality of buffers for inverting the inputted cadence signal so as to provide an inverted cadence signal to said buffer means. 
     
     
       9. The device according to  claim 7 , further comprising idle pattern supplying buffer means disposed on a line for applying a cadence signal from the cadence table for supplying an idle pattern, the idle pattern supplying buffer means being enabled if “on (continuous)” data are applied thereto, and wherein noise components are not generated if the tones signals outputted through said plurality of buffers comprises an “off (intermittent)” signal. 
     
     
       10. The device according to  claim 9 , further comprising latch means connected between said plurality of tone tables and said buffer means for performing a latch operation relative to data passing from said plurality of tone tables to said buffer means. 
     
     
       11. The device according to  claim 9 , further comprising inverter means disposed on a line applying a cadence signal to be inputted to said buffer means for inverting the inputted cadence signal so as to provide an inverted cadence signal to said buffer means. 
     
     
       12. The device according to  claim 9 , further comprising cadence selecting circuit means connected between said cadence table and said idle pattern supplying buffer means and responsive to a tone-select signal from said first counter means for performing a cadence selection operation, and for supplying said “on (continuous)” data to said idle pattern supplying buffer means. 
     
     
       13. The device according to  claim 7 , further comprising latch means connected between said plurality of tone tables and said buffer means for performing a latch operation relative to data passing from said plurality of tone tables to said buffer means. 
     
     
       14. The device according to  claim 7 , further comprising inverter means disposed on a line applying a cadence signal to be inputted to said buffer means for inverting the inputted cadence signal so as to provide an inverted cadence signal to said buffer means.